Have people considered the idea that Pym and Janet just won't be in the MCU at all? Just because we are getting an Ant-Man movie following Age of Ultron doesn't mean that Pym has to wear the suit. They could just as easily use Eric O'Grady and his S.H.I.E.L.D roots, which has little connection to Ultron at all.

I would obviously prefer Pym and Janet but I won't explode if we see someone else in his place.

I have considered it. Without creating Ultron, Pym might as well not even exist. Also they might as well not even name him "Ultron." Super-Adaptoid works just as well in this case.